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United States Patent |
6,183,320
|
Natsume
|
February 6, 2001
|
Tilt mechanism for marine outboard drive
Abstract
A tilt mechanism for a marine outboard drive includes a hydraulic cylinder
assembly disposed transversely offset from the center axis of the tilt
mechanism. The tilt mechanism includes a swivel bracket carrying a drive
unit for pivotal movement about a generally vertically extending steering
axis and a clamping bracket supporting the swivel bracket for pivotal
movement about a generally horizontally extending tilt axis. The swivel
bracket has wall portions transversely extending from the steering axis.
One of the wall portions positioned nearer to the hydraulic cylinder
assembly is reinforced greater than the other wall portion. Also, the
clamping bracket comprises a pair of spaced members. One of the spaced
members positioned nearer to the hydraulic cylinder assembly is reinforced
greater than the other spaced member.
Inventors:
|
Natsume; Noriyuki (Shizuoka, JP)
|
Assignee:
|
Sanshin Kogyo Kabushiki Kaisha (JP)
|
Appl. No.:
|
385177 |
Filed:
|
August 30, 1999 |
Foreign Application Priority Data
| Sep 07, 1998[JP] | 10-252989 |
Current U.S. Class: |
440/53; 440/61R |
Intern'l Class: |
B63H 005/125 |
Field of Search: |
440/53,61,58-60,900
123/195 P
248/640-643
|
References Cited
U.S. Patent Documents
5529519 | Jun., 1996 | Nakamura et al. | 440/61.
|
Primary Examiner: Swinehart; Ed
Attorney, Agent or Firm: Knobbe, Martens, Olson & Bear, LLP
Claims
What is claimed is:
1. A tilt mechanism for a marine outboard drive comprising a swivel bracket
carrying a drive unit for pivotal movement about a generally vertically
extending steering axis, said swivel bracket having wall portions
extending generally transversely at both sides of said steering axis, a
clamping bracket supporting said swivel bracket for pivotal movement about
a generally horizontally extending tilt axis, said clamping bracket having
a pair of transversely spaced members adapted to be affixed to the transom
of an associated watercraft, said wall portions of said swivel bracket at
least partially being capable to be fitted between said transversely
spaced members, a hydraulic cylinder assembly being capable to expand and
contract along its longitudinal axis, said hydraulic cylinder assembly
having a pair of end portions, one of said end portions being pivotally
connected to said swivel bracket and the other one of said end portions
being pivotally connected to said clamping bracket, said hydraulic
cylinder assembly being biased to one of said transversely spaced members,
and at least one of said wall portions and said transversely spaced
members positioned nearer to said hydraulic cylinder assembly being
reinforced greater than the other one of said wall portions and said
transversely spaced members.
2. A tilt mechanism as set forth in claim 1 wherein the other one of said
wall portions has a recess at its transverse end.
3. A tilt mechanism as set forth in claim 2 further comprising a tilt stop
lever for supporting said drive unit at the fully tilted up position, and
at least a part of said tilt stop lever being positioned at said recess.
4. A tilt mechanism as set forth in claim 1 wherein each one of said
transversely spaced members includes a foot section being capable to be
seated at the transom of the associated watercraft and a standing section
extending from said foot section, and one of said standing sections
positioned nearer to said hydraulic cylinder assembly is reinforced
greater than the other one of said standing sections.
5. A tilt mechanism as set forth in claim 4 wherein both of said standing
sections are provided with at least one rib, and the number of said ribs
provided at said standing section positioned nearer to said hydraulic
cylinder assembly is more than the number of said ribs provided at the
other standing section.
6. A tilt mechanism as set forth in claim 5 wherein both sides of each of
said ribs are formed as hollows opening toward generally outwardly.
7. A tilt mechanism as set forth in claim 4 wherein said respective
standing sections have bores to receive a pivot shaft of said swivel
bracket, and a portion located in proximity to said bore of said standing
section positioned nearer to said hydraulic cylinder assembly is
reinforced greater than another portion located in proximity to said bore
of the other standing section.
8. A tilt mechanism as set forth in claim 7 wherein said respective
portions are configured as curves.
9. A tilt mechanism as set forth in claim 4 wherein said respective
standing sections have bores, a pivot shaft of the other one of said end
portions of said hydraulic cylinder assembly is journaled in said bores,
the other one of said end portions of said hydraulic cylinder assembly is
disposed on said pivot shaft at generally directly next to one of said
transversely spaced members, and the reminder of space on said pivot shaft
is balanced with a collar.
10. A tilt mechanism as set forth in claim 1 further comprising a powering
assembly for expanding and contracting said hydraulic cylinder assembly,
and said powering assembly being disposed between said hydraulic cylinder
assembly and one of said transversely spaced members that is positioned
farther from said hydraulic cylinder assembly than the other one of said
transversely spaced members.
11. A tilt mechanism for a marine outboard drive comprising a swivel
bracket carrying a drive unit for pivotal movement about a generally
vertically extending steering axis, a clamping bracket supporting said
swivel bracket for pivotal movement about a generally horizontally
extending tilt axis, said clamping bracket having a pair of transversely
spaced members adapted to be affixed to the transom of an associated
watercraft, a hydraulic cylinder assembly being capable to expand and
contract along its longitudinal axis, said hydraulic cylinder assembly
having a pair of end portions, one of said end portions being pivotally
connected to said swivel bracket and the other one of said end portions
being pivotally connected to said clamping bracket, said hydraulic
cylinder assembly being disposed between said transversely spaced members
and biased to one of said transversely spaced members, each of said
transversely spaced members including a foot section being capable to be
seated at the transom of the associated watercraft and a standing section
extending from said foot portion, said respective standing sections having
bores, a pivot shaft of the other one of said end portions of said
hydraulic cylinder assembly being journaled in said bores, the other one
of said end portions of said hydraulic cylinder assembly being disposed on
said pivot shaft at generally directly next to one of said transversely
spaced members, and the reminder of space on said pivot shaft being
balanced with a collar.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a trim and/or tilt mechanism for a marine
outboard drive and more particularly to an improved trim and/or tilt
mechanism that includes a hydraulic cylinder device disposed transversely
offset from the center axis of the mechanism per se.
2. Description of Related Art
As an example of the marine outboard drive, generally an outboard motor has
a drive unit mounted on an associated watercraft by means of a trim and/or
tilt mechanism which comprises a swivel bracket and a clamping bracket.
The swivel bracket carries the outboard drive unit for pivotal movement
about a generally vertically extending steering axis. The clamping
bracket, in turn, is affixed to the transom of an associated watercraft
with a pair of horizontally spaced members and supports the swivel bracket
for pivotal movement about a generally horizontally extending tilt axis.
The trim and/or tilt mechanism includes also a hydraulic cylinder assembly
disposed between the swivel bracket and the clamping bracket so that the
swivel bracket as well as the drive unit is tilted up or down relative to
the clamping bracket and eventually to the transom of the associated
watercraft. The fluid motor is, for example, a compound trim and tilt
hydraulic cylinder device. An exemplary hydraulic cylinder device is shown
in the U.S. Pat. No. 5,718,613.
The hydraulic cylinder device includes an outer cylinder housing, a tilt
cylinder slidably supported in the outer cylinder housing, a tilt piston
slidably supported in the tilt cylinder and a piston rod affixed to the
tilt piston at its one end and extending outwardly from both of the tilt
cylinder and the outer cylinder housing. The other end of the piston rod
is pivotally connected to the swivel bracket, while the outer cylinder
housing is also pivotally connected to the clamping bracket. Hydraulic
fluid is contained in the cavities formed in the cylinder housing and also
the tilt cylinder and pressurized selectively by a powering assembly to
move the piston rod either one of the expanding direction or contracting
direction.
By this selective movement of the piston rod, the drive unit can be lifted
up or lowered down. If an operator of the outboard motor wishes to adjust
the trim angle of the drive unit, the operator operates the hydraulic
cylinder device within a trim range. During this trim range operation, the
tilt cylinder acts as a trim piston and moves relatively slow but produces
large force. Meanwhile, if the operator wishes to tilt up or down the
drive unit, he or she operates the hydraulic cylinder device within a tilt
range. In this range, the tilt piston moves and this time relatively quick
but produces small force.
As described above, the mechanism will operate as a trim and tilt mechanism
with this hydraulic cylinder device. Some mechanism, however, is provided
with either a trim cylinder device or a tilt cylinder device. Thus, the
term "tilt mechanism" will mean not only the tilt mechanism per se but
also the trim and tilt mechanism and even a single trim mechanism in the
broad sense hereunder wholly through this specification including claims
unless depicted otherwise.
The powering assembly comprises a reversible electric motor, a reversible
hydraulic pump driven by the electric motor and a fluid reservoir. In
order to minimize the size of the tilt mechanism, usually the powering
assembly is placed between the spaced members of the clamping bracket side
by side with the hydraulic cylinder device. Since the place for the
hydraulic cylinder device and the powering assembly is not so spacious, it
means that the hydraulic cylinder device must be decentered transversely
from the axis of the tilt mechanism. This arrangement gives rise to a
problem.
That is, the lifting or lowering force exerted onto the piston rod and the
outer cylinder housing affects the swivel bracket and the clamping bracket
as an offset load and this offset load is likely to deform the bracket
assembly. If the brackets have sufficient thickness entirely, rigidity
will be enough. However, this resolution apparently increases the whole
weight of the bracket assembly.
It is, therefore, a principal object of this invention to provide an
improved tilt mechanism to solve the problem.
It is another object of this invention to provide a tilt mechanism that
will hardly cause such a deformation in its bracket assembly without
having futile weight.
SUMMARY OF THE INVENTION
In accordance with one aspect of this invention, a tilt mechanism for a
marine outboard drive comprises a swivel bracket. The swivel bracket
carries a drive unit for pivotal movement about a generally vertically
extending steering axis. The swivel bracket has wall portions extending
generally transversely at both sides of the steering axis. The tilt
mechanism also includes a clamping bracket. The clamping bracket supports
the swivel bracket for pivotal movement about a generally horizontally
extending tilt axis. The clamping bracket has a pair of transversely
spaced members adapted to be affixed to the transom of an associated
watercraft. The wall portions of the swivel bracket are at least partially
capable to be fitted between the spaced members. The tilt mechanism
further comprises a hydraulic cylinder assembly. The hydraulic cylinder
assembly is capable to expand and contract along its longitudinal axis.
The hydraulic cylinder assembly has a pair of end portions. One of the end
portions is pivotally connected to the swivel bracket and the other one of
the end portions is pivotally connected to the clamping bracket. The
hydraulic cylinder assembly is biased to one of the transversely spaced
members. At least one of the wall portions and the transversely spaced
members positioned nearer to the hydraulic cylinder assembly is reinforced
greater than the other one of the wall portions and the transversely
spaced members.
In accordance with another aspect of this invention, a tilt mechanism for a
marine outboard drive comprises a swivel bracket. The swivel bracket
carries a drive unit for pivotal movement about a generally vertically
extending steering axis. The tilt mechanism also comprises a clamping
bracket. The clamping bracket supports the swivel bracket for pivotal
movement about a generally horizontally extending tilt axis. The clamping
bracket has a pair of transversely spaced members adapted to be affixed to
the transom of an associated watercraft. The tilt mechanism further
comprises a hydraulic cylinder assembly. The hydraulic cylinder assembly
is capable to expand and contract along its longitudinal axis. The
hydraulic cylinder assembly has a pair of end portions. One of the end
portions is pivotally connected to the swivel bracket and the other one of
the end portions is pivotally connected to the clamping bracket. The
hydraulic cylinder assembly is disposed between the transversely spaced
members and biased to one of the transversely spaced members. Each of the
transversely spaced members includes a foot section being capable to be
seated at the transom of the associated watercraft. Each of the
transversely spaced members also includes a standing section extending
from the foot portion. The respective standing sections have bores. A
pivot shaft of the other one of the end portions of the hydraulic cylinder
assembly is journaled in the bores. The other one of the end portions of
the hydraulic cylinder assembly is disposed on the pivot shaft at
generally directly next to one of the transversely spaced members. The
reminder of space on the pivot shaft is balanced with a collar.
Further aspects, features and advantages of this invention will become
apparent from the detailed description of the preferred embodiments which
follow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view showing an outboard motor embodying
features of this invention as attached to the trnsom of an associated
watercraft shown partially in phantom.
FIG. 2 is an enlarged front elevational view of a tilt mechanism
constructed in accordance with an embodiment of this invention. Some
portions are shown in cross-section.
FIG. 3 is an enlarged outside elevational view of one clamping bracket
member positioned at the starboard.
FIG. 4 is an enlarged inside elevational view of the same clamping bracket
member as shown in FIG. 3.
FIG. 5 is a cross-sectional view of the same clamping bracket member taken
along the line 5--5 in FIG. 3.
FIG. 6 is a cross-sectional view of the same clamping bracket member taken
along the line 6--6 in FIG. 4.
FIG. 7 is an enlarged outside elevational view of the other clamping
bracket member positioned on the portside.
FIG. 8 is an enlarged inside elevational view of the same clamping bracket
member as shown in FIG. 7.
FIG. 9 is a cross-sectional view of the same clamping bracket member taken
along the line 9--9 in FIG. 7.
FIG. 10 is a cross-sectional view of the same clamping bracket member taken
along the line 10--10 in FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Referring now in detail to FIGS. 1 through 10 which illustrate an
embodiment of this invention and initially to FIG. 1, an outboard motor is
identified generally by the reference numeral 20. The outboard motor 20 is
shown as attached to a transom 22 of an associated watercraft 24 that is
shown partially. A hydraulic trim and tilt adjustment mechanism is
identified generally by the reference numeral 26 and will be described
more in detail with reference to FIGS. 2 through 10 later.
Although the invention is described in conjunction with the outboard motor
20, it should be readily apparent that the invention is susceptible of use
with other types of outboard drives such as the outboard drive portion of
an inboard, outboard drive. It is believed that other usages will be
readily obvious to those skilled in the art.
The outboard motor 20 includes a power head 28 which comprises a powering
internal combustion engine (not shown) and a surrounding protective
cowling 30. As is typical with outboard motor practice, the engine of the
power head 28 is supported so that its output shaft rotates about its
vertically extending axis and drive a driveshaft 34 that is journaled
within a driveshaft housing 36. The driveshaft 34 extends through the
driveshaft housing 34 and into a lower unit 38 and there drives a
propulsion device such as a propeller 40 affixed on a propeller shaft 41
through a conventional forward/neutral/reverse transmission 42.
A steering shaft 44 is affixed to a driveshaft housing 36 and is supported
for steering movement within a swivel bracket 48 in a known manner. The
steering shaft 44 is accommodated in a steering shaft holder portion 49 of
the swivel bracket 48. The swivel bracket 48 has a forwardly extending
portion 50 that is connected by means of a pivot pin 52 to a clamping
bracket 54. Thus, the swivel bracket 48 carries the drive unit 58 for
pivotal movement about a generally vertically extending steering axis 59
of the steering shaft 44, while the clamping bracket 54 supports the
swivel bracket 48 for pivotal movement about a generally horizontally
extending tilt axis of the pivot pin 52. The clamping bracket 54 is
detachably affixed to the transom 22 in a manner that will be described
shortly. The swivel bracket 48 and the clamping bracket 54 define a
bracket assembly 56.
The power head 28, the driveshaft housing 36 and the lower unit 38 except
for the bracket assembly 56 define a drive unit 58. The pivotal connection
52 between the clamping bracket 54 and the swivel bracket 48 permits the
drive unit 58 to be moved through a trim adjusted range that exists
between the fully trimmed down position to the flully trimmed up position.
In addition, the drive unit 58 may be swung through a remaining range to a
tilted up out of the water position about the pivot pin 52. A hydraulic
tilt and trim cylinder assembly or device 60 is provided for effecting
these movements and other movements such as a pop up movement when an
underwater obstacle is struck to the drive unit 58.
The cramping bracket 54 actually comprises a pair of transversely spaced
apart side members 64, 66 that are mounted on the rear of the transom 22.
The side member 64 is located at the starboard, while the other side
member 66 is located on the port side. The swivel bracket 48 is interposed
between them. That is, the swivel bracket 48 has wall portions 70, 72 that
extend generally transversely at both sides of the steering shaft holder
portion 49. The forwardly extending portion 50 is bound up with these wall
portions 70,72 at the top of the swivel bracket 48. The steering shaft 44
has the aforenoted steering axis 59. This axis 59 is consistent with the
center axis of the hydraulic trim and tilt adjustment mechanism 26 in the
front view as shown in FIG. 2. Thus, the center axis of the tilt mechanism
26 will be indicated with the same reference numeral 59 hereunder.
The hydraulic trim and tilt cylinder assembly 60 is nested between the side
members 64, 66 but positioned transversely offset from the steering or
center axis 59 toward the starboard side member 64. The center axis 76 of
the cylinder assembly 60 is, thus, located apart from the center axis 59
with the distance (D). The reminder of the space is occupied generally by
a powering assembly 77 so that both of the hydraulic cylinder assembly 60
and the powering assembly 77 are disposed side by side. That is, the
hydraulic cylinder assembly 60 occupies almost the half space that extends
at the starboard side from the center axis 59 and the powering assembly 77
occupies the other half space that extends on the port side from the axis
59.
The hydraulic cylinder assembly 60 forms an integral part with the powering
assembly 77. The powering assembly 77 includes a reversible electric motor
78 at its upper end. A reversible hydraulic pump 80 is disposed below the
electric motor 78. A fluid reservoir 82 is also disposed beneath the pump
80 and contains hydraulic working fluid for the system. In addition, a
suitable valve assembly may be incorporated within the pump 80 and the
reservoir 82 so as to provide normal pressure relief functions and
directional control of the hydraulic cylinder assembly 60.
The hydraulic cylinder assembly 60 includes an outer cylinder housing 86
having a trunion portion 88 with a bore 90 so as to receive a lower pin 91
for providing a pivotal connection to the clamping bracket 54 and
specifically the side members 64, 66 thereof. Bores 92, 93 of the side
members 64, 66 receive the lower pin 91. A pair of bushes 94 are fitted
around the lower pin 91. The bushes 94 are separated at the center axis 59
from each other and each has a flange 96 at the outer side. The bushes 94
are made of metal such as, for example, stainless steel (SUS). Meanwhile,
another pair of bushes 98 are provided around and at both sides of the
lower pin 91 to be fitted into the bores 92, 93 of the side members 64,
66. Each of these bushes 98 have a flange that meets with the respective
flanges 96 of the bushes 94. The bushes 98 are also made of metal such as,
for example, stainless steel (SUS). Thus, the lower pin 91 is journaled by
the side members 64, 66 and pivotally supports the trunion 88 of the
cylinder housing 86. A collar 102 is fitted around the outer side of one
of the bushes 94 so as to balance the distance between the trunion 88 of
the cylinder housing 86 and the side member 66 located on the port side.
In other words, the trunion 88 is accurately positioned on the lower pin
91 with the collar 102 and the flange 96 of the bush 94. Because of this
arrangement, no rattling of the outer housing 86 is produced.
As described above, since the metal bushes 94, 98 are fitted around the
lower pin 91, the pin 91 is reinforced against the bending force exerted
thereon in the decentered arrangement of the hydraulic cylinder assembly
60.
Although any internal arrangement is available, the hydraulic cylinder
assembly 60 in this embodiment is a compound or telescopic trim and tilt
cylinder device that is conventional and it is, for example, disclosed in
the U.S. Pat. No. 5,718,613 as aforenoted. The hydraulic cylinder device
60 contains a tilt cylinder slidably supported in a cavity of the outer
cylinder housing 86, a tilt piston slidably supported in a cavity of the
tilt cylinder and a piston rod 110 affixed to the tilt piston at its one
end and extending outwardly from both of the tilt cylinder and the outer
cylinder housing 86.
The tilt piston has valving passages for effecting, for example, a shock
absorbing function in case of an abrupt hit to the drive unit 58 by an
underwater obstacle. Also, the outer cylinder housing 86 has a passage
that connects via the powering assembly 77 upper and lower chambers formed
in the cavity and generally divided by the tilt piston. The passage is
formed at a wall portion of the outer housing 86. Working fluid
pressurized by the powering assembly 77 will be supplied through the
passage to the upper and lower chambers to move the tilt piston. This
causes the expanding and contracting movements of the piston rod 110.
The piston rod 110 has a trunion portion 112 with a bore 114 that receives
an upper pin 116 for providing a pivotal connection to the swivel bracket
48 and specifically a pair of spaced portions 118 and 120 thereof A pair
of bushes 122, which have configurations similar to the bushes 94 are
inserted between the upper pin 116 and the bore 114 of the trunion 112.
Another pair of bushes 124, which have configurations similar to the
bushes 98 are also inserted between the upper pin 116 and bores of the
spaced portions 118, 120. These bushes 122, 124 can be made of, for
example, metal or synthetic resin.
With the aforedescribed connections, when the piston rod 110 expands
outwardly from the outer cylinder housing 86, the swivel bracket 48 and
also the drive unit 58 supported by the swivel bracket 48 are lifted up
within the trim adjusted range and further the tilt range. Also, when the
piston rod 110 contacts into the outer housing 86, the swivel bracket 48
as well as the drive unit 58 are lowered down within the same ranges.
The hydraulic tilt cylinder assembly 60 is decentered and more specifically
disposed transversely offset from the center axis 59 of the hydraulic tilt
adjustment mechanism 26 as described above. In other words, the hydraulic
tilt cylinder assembly 60 is biased to a starboard side member 64. Due to
this arrangement, the lifting or lowering force exerted onto the piston
rod 110 and the outer cylinder housing 86 affects the swivel bracket 48
and the clamping bracket 54 as an offset load. This offset load is likely
to deform the bracket assembly 56.
In order to avoid the deformation, the bracket assembly 56 has improved
configurations. These configurations will now be described with reference
to FIGS. 2 through 10.
Firstly, the port side wall portion 72 of the swivel bracket 48, which is
positioned farther from the hydraulic cylinder assembly 60 than the
starboard side wall portion 70, has a recess 130 at its transverse end.
This means that the starboard side wall portion 70 is reinforced greater
than the port side wall portion 72. At this port side wall portion 72, a
bore 132 is provided. A tilt stop lever 134 is pivotably inserted into
this bore 132 and its head portion 136 is positioned in the recess 130.
This tilt stop lever 134 is conventional and for holding the drive unit 58
at the fully tilted up position mechanically by positioned at a step
portion 137 formed at the top of the side member 66. Thus, the recess 130
contributes not only for reinforcement of the starboard side wall portion
70 relative to the port side wall portion 72 but also for compactness of
the hydraulic tilt mechanism 26. In addition, the port side wall portion
72, conversely, has a weight lighter than a weight of the starboard side
wall portion 70. This contributes to reduce the whole weight of the swivel
bracket 48.
Another improvement exists in configurations of the side members 64, 66 of
the clamping bracket 54.
The respective side members 64, 66 are configured generally as a L-shape in
a side elevational view as seen in FIGS. 3, 4, 7 and 8. That is, the upper
portions in proximity to bores 140, 142, through which the pivot pin 52
extends, are curved to make a generally right angle. The respective side
members 64, 66 have foot sections 144, 146, with which the side members
64, 66 are seated at the transom 22 of the associated watercraft 24. The
respective side members 64, 66 have also standing sections 148, 150 that
extend from the foot sections 144, 146. The foot sections 144, 146 extend
simply outwardly. That is, transverse cross-sections of the side members
64, 66 are configured as a generally L-shape. Hook portions 152, 154 are
provided for assuring the installation of the clamping bracket 54 to the
transom 22 of the associated watercraft 24.
As best seen in FIG. 3, the standing section 148 of the starboard side
member 64 has hollow portions 156 that are recessed at the curved section.
Ribs 158 are formed between the respective hollow portions 156. The hollow
portions 156 open outwardly as seen in FIG. 5. The length distance (S)
from the centroidal axis (X) of the starboard side member 64 proximate the
hollow portions 156 to the point of action (Z) of the exerting force,
which exists on the center axis 76, is less than the distance (L) from the
centroidal axis (Y) of the starboard side member 64 in other locations to
the same center axis 76 Accordingly, the bending moment exerted upon the
side member 64 is smaller than the bending moment that would be produced
if the hollow portions 156 were not provided. Thus, by decreasing the
section modulus of the starboard side member 64, the maximum bending
stress that can be accommodated is increased. This means that the
starboard side member 64, particularly the curved portion thereof, is
reinforced.
In addition, as best seen in FIG. 7, the port side member 66 has only a
couple of hollow portions 160, in other words, only one rib 162
therebetween. That is, the starboard side member 64 is reinforced greater
than the port side member 66. Thus, the bending force exerted upon the
starboard side member 64 is effectively absorbed by the multiple ribs 158
thereon. Conversely, the port side member 66 is lighter than the starboard
side member 64 because it has no unnecessary reinforcement. The hollow
portions 160 also open outwardly as shown in FIG. 9.
In the meantime, the bottom portions of the standing sections 148, 150 are
provided with the bores 92, 93 through which the lower pin 91 extends. As
best seen in FIGS. 4 and 8, both portions in proximity to these bores 92,
93 are reinforced with a couple of ribs 166, 168. However, only the
periphery of the bore 92 is further reinforced with a bank portion 170
formed around it. Accordingly, the bottom portion of the starboard side
member 64 is more rigid than the same portion of the port side member 66.
As described above, in the bracket assembly 56, only the portions those
substantially need reinforcement have configurations that increase
rigidity. Thus, the reinforcement is achieved without increasing
unnecessary weight.
A plurality of apertures or recesses 174 (see FIG. 2) are formed on the
respective foot sections 144, 146 of the side members 64, 66. These
apertures or recesses 174 are useful to reduce the whole weight of the
clamping bracket 54 further.
Also, the respective standing sections 148, 150 have a plurality of
apertures 176, 178 through which a trim stopper pin (not shown) will be
inserted to keep the drive unit 58 at a suitable trim angle selectively
and mechanically.
Of course, the foregoing description is that of a preferred embodiment of
the invention, and various changes and modifications may be made without
departing from the spirit and scope of the invention, as defined by the
appended claims.
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